New U.S. sanctions on Venezuela’s oil production are expected to further crimp the country’s output and reduce global supply even more than sanctions on Iran—a development that could provide another boost to rising crude prices.

Oil prices in the U.S. have risen more than 19% this year to $72.13 a barrel, driven in large part by OPEC cutbacks and supply disruptions. These forces, along with rising global demand for oil, have combined to shrink what had been a supply glut that dragged down U.S. prices below $30 a barrel in...